Rs. Premachandran et Sg. Malghan, DISPERSION CHARACTERISTICS OF CERAMIC POWDERS IN THE APPLICATION OF CATIONIC AND ANIONIC POLYELECTROLYTES, Powder technology, 79(1), 1994, pp. 53-60
Dispersion characteristics of silicon nitride, silicon carbide, alumin
a, aluminum nitride and yttria powders in aqueous solutions of anionic
and cationic polyelectrolytes were studied by measuring particle size
distribution using a gravity sedimentation technique. The influence o
f polyelectrolyte concentration and suspension pH on the dispersion wa
s examined. All powders examined in this study could be well dispersed
in the presence of either cationic or anionic polyelectrolyte by adju
sting the dispersion pH to at least 2.5 pH units away from the effecti
ve pH(iep) (iep=isoelectric point) of the powder-polyelectrolyte syste
m. The dispersion characteristics of these powders in the presence of
polyelectrolytes are explained in terms of interfacial interactions in
the powder-polyelectrolyte systems. These interactions between the po
wder and polyelectrolytes as a function of suspension pH, and possible
mechanisms leading to the stability of particles in a dispersion, are
discussed.